Apparatus for producing seamless tubes



1949- E; c. SLEEMAN 2,458,110

APPARATUS FOR PRODUCING SEAMLESS TUBES Filed Nov. 7, 1944 s Sheets-Sheet'1 Jan. 4, 1949. c, SLEEMAN 2,458,110

APPARATUS FOR PRODUCING SEAMLESS TUBES 3 Sheets-Sheet 2 Filed Nov. 7,1944 1; t n 28 3D 34 d 46 :2 f 3 42 If 40 l 5 4 r "f c v B s I" 1L :15-

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Jan. 4, 1949. E. c. SLEEMAN APPARATUS FOR PRODUCING SEAMLESS TUBES 3Sheets-Sheet 5 Filed Nov, -'7, 1944 h awe/M307, tA/PL C. JLMMAN 351312/; Gum;

Patented Jan. 4, 1949 APPARATUS FOR PRODUCING SEAMLESS TUBES Earl 0.Bloom, Detroit, Micln, assignor to Detroit Seamless Steel Tubes Company,Detroit, Mich a corporation of Michigan Application November 7, 1944,Serial No. 582,309

'1 Claim. 1

This invention relates to an improved method 7 and apparatus forproducing seamless tubes of ferrous and non-ferrous metals in a rollmill.

In the manufacture of seamless tubes there are several methods and typesof apparatus now in use for performing the operations required vis:reducing the diameters, reducing the wall thickness, increasing thelength and smoothing the outer and inner surfaces.

One method consists in passing a heated pierced seamless tube back andforth two or three times between a pair of rotating round rolls providedwith grooves that form a substantially round opening and over a shortround plug that is located in the opening. The plug is mounted on theend of a mandrel bar which is fixed relative to the longitudinalmovement of the tube. Passing the tube through the rolls and over theplug produces a tube having a reduced diameter, a reduced wallthickness, and an increased length. The tube is then passed betweenanother pair of rotating rolls that have their axes crossed and over alongitudinallyflxed, short, round plug 10- cated in the space betweenthe rolls. This performs the operation of smoothing the outer and innerdiameters. This method is limited and produces uncontrollable defects inthe finished tube in that there is a tendency of the tube to overflllthe groove, causing fins and laps to be formed on the outer surafce,formation of tears and scratches on the inner surface due to the slidingaction between the tube and plug,' a reduction of the feed of the tubebetween the rolls due to the resistance of the plug, a limited number ofpasses that can be made due to the loss of heat in the tube, andexcessive wear on the-plug.

Another method consists in placing the heated pierced seamless tube on asolid round mandrel M bar, then passing the tube and bar between a. pairof rotating rolls havingtheir axes crossed and simultaneously passingthe tube and mandrel bar between a pair of rotating discs positionedbetween the rolls and above and below the tube. The peripheral speed ofthe discs is considerably greater than that of the rolls' and theirdirection of travel is opposed to that of the rolls and the rotation ofthe tube. This method and apparatus is also limited and producesuncontrollable defects in the finished seamless tube. Such defects causethe formation of scratches and other marks on the outer surface of thetube due to the opposed action of the discs on the rotating and forwardfeed'of the tube, excessive wear on the periphery of the discs due tothe difierence in speed, and difficulty in keeping the discs in coriiirect position in relation to the rolls and to the pass line along whichthe tube and mandrel bar travel. This is particularly true whenproducing tubes of small diameters which require discs oi narrow width.

A further method consists in placing the heated pierced seamless tube ona solid round mandrel bar and passing the tube and bar between a groupof three rotating rolls having their axes crossed. .The rolls areequally spaced around the tube and bar and form a working pass whichproduce a seamless tube. This method is unsatisfactory for producingfinished seamless tubes or small diameters and thin walls. The relationof the outside diameter of the tube to the maximum roll diameter beingapproximately one to five it is apparent that to produce a small outsidediameter tube it is impractical to mount the roll-s due to theirrestricted diameters. Due to the unsupported portions of the tubecircumference in the pass the amount of wall thickness reduction is alsolimited. Large reductions cause the tube to bulge outwardly between thepoints of support and restrict it from rotating and feeding forwardly.

It is an object of the present invention to overcome the above listeddifficulties and to provide new and useful apparatu which will producefinished seamless tubing in a manner which will not result in any of thedefects as are produced with the methods and apparatus now in use.

Another object of the invention is to provide apparatus which willreduce the diameter of the tube, reduce the wall thickness. increase thelength of the tube, and produce smooth outer and inner surfaces by asingle pass of the tube through the apparatus.

- working passes in close proximity along the line of travel of the tubeand the mandrel bar and to rotate and draw the mandrel bar and tubethrough the rolls by the rotation of the rolls in peripheral frictionalengagement with the tube.

Other objects and advantages of the invention will be more apparent fromthe following description taken in connection with the accompanyingdrawings in which:

Fig.1;is a top plan view of that portion of a roll-mill; which embodiesthe present invention;

Fig. 2 is a side elevation of P18. 1; V Fig. 3 is an end view of theapparatus shown in Figs. 1 and 2;

Fig. 4 is an enlarged-fragmentary viewtaken on line -il of Fig. 3;

- amen-1o f I members 42, M, and 46 are arranged adjacent the workingstations A, B, and C respectively and are positioned between the rollsas indicated in Fig. 5 is a view similar to Fig. 4 but taken on line5--5 of Fig. 3;

Fig. 6 is a sectional view taken on line 8-8 of Fig. 4;

Fig. 7 is a sectional view taken on line 'l--I of Fig. 4;

Fig. 8 is a sectional view taken on line 88 of Fig. 4;

Fig. 9 is a sectional view taken on line 8-9 of Fig. 4;

Fig. 10 is a sectional. view taken on line iii- 40 of Fig. 5;

. Fig. 11 is a sectional view taken on line ll-ll of Fig. 5;

Fig. 12 is a sectional view taken on line [2-42 of Fi 5;

Fig. 13 is a sectional view taken on line |8l3 of Fig. 4; and

Fig. 14 is a sectional view taken on line il-H of Fig. 4.

Referring to. the drawings, only that portion diameters and requiredwall thickness of the tube.

Inoperation, 9. pierced seamless tube T, heated to the propertemperature, is placed in the end guide 38. A solid or hollowmandrel'bar 50, having a length greater than the finished seamless tubeT, is pushed through the pierced tube T in the direction shown by thearrow D in Fig. 4 until its end is in line with the end of the guide 40and retained in that position. The pierced seamless of the apparatusessential to'the invention has been illustrated. The drive mechanism,associated shafts, gears, etc., of roll mills, well known in the art,have been omitted and the operation of the device illustrated will bereadily understood.

Four rotatable shafts 28, 22, 24, and 26 have been arranged around acentral point which is the pass line X through which the tube to beformed passes longitudinally. The axes of the shafts 20, 22, 26, and 26are positioned at angles of ninety degrees to each other around thelongitudinal axis of the pass line X. The axes of the shafts 20 and 22are positioned diametrically opposite and are each provided with axiallyspaced rolls 28 and 30. The axis of the shaft 28 extends at an angle tothe axis of the pass line X and the axis of the shaft 22 extends at anangle to the axis of the pass line X but in a direction opposite to thatangle between the shaft 22 and the pass line X.

The axes of the shafts 2B and 26 are positioned diametrically oppositeand are each provided with a roll 32. The axes of the shafts 2d and 28extend at an angle to the axis of the pass line X and each in oppositelyextending directions. The axes of the shafts 2'0, 22, 24, and 26 may beradially adjustable and the diameters of the rolls 28, 30, and 32 are ofa diameter to engage the outer periphery of the tube being worked uponwhen the shafts are disposed in proper position. The rolls 32 arepositioned between the axially spaced rolls 28 and 30.

By this arrangement it will be noted that there have been provided threeworking stations, designated at A, B, and C, with the rolls contactingthe outer periphery of the tube T at diametrically opposite points ofthe tube T. The rolls 28 form the working station A, the rolls 38 formthe working station 0, and the rolls 32 form the working station B.

The rolls are each provided with a cylindrical surface 34 and a conicalsurface 38 both of which are coaxial withthe axis of its respectiveshaft.

Tubular end guides 38 and 48 are provided for receiving and guiding thetube T through the working stations. oppositely disposed guide tube T isthen pushed in the direction of the arrow D between the conical surfaces30 of the rolls 28 at the working station A.

The pierced tube T on reaching point M is gripped :by the diametricallyopposed rolls 28. The rolls are rotating'at the same peripheral speedand the rotation and gripping action causes the tube to rotatein thedirection indicated by the arrow E. Due to the angularly related axes ofthe shafts and rolls, sometimes referred to in the art as askew, and therotation of the rolls,

the tube is fed toward the left in a direction indicated by the arrow D.

As the rotation and forward feed of the tube T continues, reductions inthe outer and inner diameters occur and continues with no change in thewall thickness. until the tube T reaches the diametrically opposedpoints N. At this point a reduction of the outer diameter and wallthickness occurs. At the points N the inner diameter of the tube T, dueto the pressure of the rolls, grips the round mandrel bar 50 and startsit rotating in the direction indicated by the arrow E at approximatelythe same rotating speed as that of the tube T at these points. Themandrel bar 50 also starts to feed forwardly in the direction of thearrow D due to the contact between the inner diameter of the tube T andthe mandrel bar 58. I

As the metal in the tube T and the mandrel bar 50 continues to rotateand move forwardly from points N to points P, the outer diameter andwall thickness are progressively reduced, the inner diameter remainingthe same. From points P to points It the inner and outer diameters andthe wall thickness remain substantially the same. The inner and outersurfaces are smoothed and any irregularities in the wall thickness arecorrected.

The tube T on leaving the first working station A, including points M,N, P, and R, assumes a substantially round form, the inner diameterbeing slightly greater than the diameter of the mandrel bar 50.

The action on the tube T at points M, N, P, and R causes the extrudedportion of the tube T to have a considerably greater forward speed, dueto its elongatiomthen that portion of the tube eritering the point M.Consequently that portion of the tube T leaving the working station A ismoving longitudinally at a greater speed than that portion of the tubeentering the working station A. It is therefore desirable to rotate therolls 32 and 36 at a diiferent speed or at a different angular positionwith respect to the axis of the pass line X. This may be accomplished byeither a difference in speed ofrotation, alteration of relative'axialangular relation or a 'combination of both to compensate for theincreased forward travel of the elongated portion of the tube T.

-As that portion of the tube T enters the second working station B, itfirst comes in contact with points 8 on the conical surfaces 36 of rolls32 and the inner periphery of the tube T is urged into contact with themandrel bar 50 as indicated by the points U and at those points theconical surfaces further reduce the wall thickness and at diametricallyopposite points engage the inner peripheryof the tube T with the outerperiphery of the mandrel bar 50. The cylindrical surfaces 34 of therolls 32 remain substantially the same throughout their rollingengagement with the outer periphery of the tube T and the wall thicknessremain substantially the same. The inner and outer surfaces are againsmoothed as by the surfaces 34 on rolls 28 and there is a furthercorrection of any irregularities of the wall thickness.

The working station B includes the points illustrated on the drawings aspoints S, U, V", and W.

The continued longitudinal movement of the tube in its finisheddimensions enters the third working station C. 'At this station thepressure is predetermined to exert only a rounding action to theelongated tube T. It will be noted that the pressure of the rolls 30 isinsufficient to contact the inner periphery of the tube with the outerperiphery of the mandrel bar 50. The cylindrical surfaces of the rolls30 contact the outer periphery of the tube T, and the portion of thetube T leaving station C is cylindrical as illustrated in Fig. 13.

The method and apparatus herein described provides for the formation ofa finished seamless tube in one pass through the device. The locationand arrangement of parts permit the re quired cross rolling operationson a pierced seamless tube in three successive operations therebyproducing a smooth finished seamless tube by reducing the, diameters,reducing the wall thick- 'ness, increasing the length and smoothing theof my invention or the method of formation, and

it is not my intention to limit its scope other than by the terms of theappended claim.

I claim:

A seamless tube rolling mill comprising, a pair of driven shaftsarranged with their axes dia- I metrically opposed with respect to apass line, a second pair of driven shafts arranged with their axesdiametrically opposed with respect to said pass line andcircumferentially spaced around said pass line from said first-namedshafts, all said shaft axes being fixed against rotation about said passline, the axes of said shafts being askew to each other and to the saidpass line, two pairs of opposed rolls axially spaced and fixed on saidfirst pair of shafts, and a pair of opposed rolls fixed to said secondpair of shafts and disposed axially intermediate the said two pairs ofrolls on said first shaft.

EARL C. SLEEMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 1 Date 240,774 Seaman Apr. 26, 1881401,144 Flagler Apr. 9, 1889 r 1,055,368 Stiefel Mar. 11, 1913 1,088,650Brinkman Feb. 14, 1914 1,520,905 Lauren Dec. 30, 1924 1,800,891 KocksApr. 14, 1931 1,977,223. Abramsen Oct. 16, 1934 2,060,087 Klamp Nov. 10,1936 FOREIGN PATENTS Number Country Date 259,623 Germany May 9, 19 33851940 Germany Nov. 30, 1923 424,211 7 Germany Jan. 19, 1926

